Sunrun and Tesla dispatched more than 580 megawatts (MW) of peak power from home batteries to California’s grid on the evening of September 9, 2026, during a heat wave that drove elevated electricity demand and rising wholesale energy prices.
The combined output marks the largest distributed power plant dispatch event on record, with enough capacity to power all households in Sacramento County during peak hours.
At the request of the California Energy Commission and California utilities, Sunrun and Tesla discharged their customers’ home batteries to the grid for a three-hour evening window to increase the grid’s operating margin and put downward pressure on real-time energy prices.
The 580 MW combined total included 517 MW from Tesla Powerwalls and 63 MW from other battery manufacturers. Of the 110,000 Powerwalls that participated, more than half are owned and operated by Sunrun.
Sunrun also dispatched more than 30,000 additional customer batteries from other manufacturers.
“This historic dispatch shows that the benefits of distributed energy go well beyond individual households as we help control the cost of electricity for all Californians and reduce the need for new costly poles and wires,” said Sunrun CEO Mary Powell, in a statement.
The event was coordinated through two statewide grid service programs: the California Energy Commission’s Demand Side Grid Support program and the California Public Utilities Commission’s Emergency Load Reduction Program.
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